Ever since Virat Kohli has become the captain of the test team, one significant tactical change India has done is to play five bowlers in away tests, especially SENA. The five-bowler theory is that to win a test match, a side needs to have five quality bowlers who can pick 20 wickets. A test match can only be won when a team picks 20 wickets.
India has been applying this theory since 2016. However, they first got to apply it in SENA when they toured South Africa in 2017-18. They risked their batting to excel in the bowling department. India's excellence in bowling was on par as they managed to get all 60 wickets in three Tests in South Africa but the risk of batting cost them two games.
But the template was set since India always remained in the game with five bowlers and they managed to win in Australia twice and are currently leading in England 2-1.